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The ascending requirement of railway passengers for fast transit to distant stations has led to the development of high-speed railway networks. Faster and longer trains with heavy axle loads are in operation, inducing stronger ground vibrations in the supporting railway infrastructure. The conventional design of railway track structures are based on the maximum displacements safely allowed in the track under the expected railway loads. However, the vibrations generated in the tracks due to railway operations should also be of concern. This study characterizes the peak particle velocities (PPVs) generated in the component strata of a ballasted railway embankment during high-speed train transit within 160 to 200 km/h. The transient response of each strata is characterized for transit of wheel load in the vibration influence zone, and temporal variation of PPVs have been logged for the transit of wheel load through a distance of 30 m on the railway track. The results from the present study indicate that railway track embankments are subject to strong ground motions during high-speed train transit, which will lead to accelerated degradation of the track structure. Ground vibrations are remnant in the railway embankment, even after passage of train wheels to farther distances. Deployment of vibration mitigation measures are recommended in sensitive locations proximate to railway lines. The particle velocities quantified in this study can be utilized by railway design authorities for estimating ground-borne railway vibrations under multiple train wheel configurations, based on the axle spacing, bogie spacing and the depth of the track under consideration.

Disposal of scrap tires is indeed a significant environmental concern worldwide. As scrap tires are durable in nature, their derivatives are recommended for various civil engineering applications. Filling materials in the embankments, drainage materials, etc., are few applications suggested by various recent studies. The present study aims to investigate the use of scrap tire derivatives (TDA) for liquefaction mitigation. The study investigates the response of the ground improved with an optimum TDA-sand mix chosen from an experimental program comprising 84 number of cyclic triaxial tests. The research was conducted utilizing the numerical software PLAXIS. The investigation included the pore pressure generation in the soil in order to investigate the liquefaction behavior of the ground. A parametric study on the thickness, number of layers and depth of the placement of the optimum mix was also conducted. It was observed that TDA addition to sand improves the damping and liquefaction resistance of the sand, whereas stiffness of the matrix is reduced. Further it was concluded that the sand TDA mix should be provided in a single layer with a small thickness and at a depth below the liquefiable layer for maximum efficiency.

Train-induced ground vibrations pose serious distress in the vicinity of urban railway tracks. The present study intends to characterize the dispersion of train-induced ground vibrations in native sub-soil supporting ballasted high-speed rail lines, at transit speeds of 160–200 km/h. Results from moving load simulations indicate that ground vibrations attenuate rapidly with increase in depth from surface level of ground. However, attenuation of vibration is found to be more gradual along the horizontal surface level of ground. Intense ground vibrations are found to be distributed along a hemi-spherical radial space surrounding the track centreline. However, these vibrations are found to attenuate rapidly in the immediate space close to the railway track, followed by a gradual attenuation at the farther locations in the ground. Isolation of vibrations within the railway embankment and the region of ground supporting the embankment is recommended for effectively mitigating ground-borne railway vibrations.

Aggregate base stabilization has been widely employed for composite pavement applications with different cementitious admixtures. These mineral inorganic materials are of different types, like commercial chemical admixture (CCA) or supplementary cementitious materials (SCMs). The current study presents a comparative analytical study to evaluate the performance of these admixtures for cementitious stabilized aggregates (CSA). Four admixtures, viz. two CCA (Ac-I and Ac-II), and two SCMs (fly ash and slag) were chosen along with cement to evaluate mechanical strength via Unconfined Compressive Strength (UCS), and Modulus of Rupture (MoR), microstructural properties via Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), scanning electron microscope (SEM), and Thermogravimetric analysis (TGA) for these admixtures, impact on the composite flexible pavement design and costs. Statistical One-way ANOVA test was conducted to determine differences in their strength development at 7 and 28 days. The addition of admixtures showed an increased degree of hydration reaction in the case of CCA and SCMs, and increased strength development in the case of SCMs, while it reduced in case of CCA at 28 days. Composite pavement design for these admixtures revealed a slight benefit of using CCA in terms of reduction of pavement layer thickness, while the minimum thickness of the bituminous layer increased for SCMs by 5 mm. Admixtures were able to resists tensile stresses due to early construction traffic plying after seven days on a short-cured CSA layer in line with cement. Application of SCMs resulted in savings of up to 16% in the cost of the CSA layer, while the cost increased by up to 30% on the application of CCA.

Retaining wall with relief shelves is being increasingly adopted to provide an economical and sustainable solution for earth retention purposes. The current study aims to evaluate the effectiveness of relief shelves in mitigating lateral thrust on a rigid, non-yielding retaining wall subjected to static surcharge loading. A comprehensive numerical parametric analysis was performed using the finite difference method to determine the optimal number, width, and position of the relief shelves for a given wall height and uniform static surcharge. The findings demonstrated that the width and position of the relief shelves substantially influence the lateral earth pressure caused by the surcharge on the wall section above the relief shelf and the backfill surface settlement profile. Consequently, the implementation of relief shelves can be considered a viable method for reducing lateral thrust on rigid, non-yielding retaining walls, as long as the parameters are optimized in accordance with the results of this study.

Disposal of the scrap tire is of great concern in many countries across the globe. Several studies have been reported in the past for effective reuse of these scrap tires. The use of scrap tire derivatives in civil engineering application is also an emerging field in the recent years. In this study, an experimental testing program was carried out to investigate the behaviour of tire chip, sand and sand–tire chips mix. The study reports the effect of tire chips inclusion on the sand properties. The materials were investigated for different characteristics like specific gravity, void ratio, water absorption, compressibility and shear behaviour. Along with the mixes, behaviour of a single tire chip was also investigated. The tire chips were reported to be highly compressible in nature and possess very low shear strength in comparison to sand. The addition of tire chips to the sand resulted in the decrease in the shear strength and increase in the compressibility of the mix. High plastic strains are also observed for mixes with tire chips content. An optimum sand–tire chips mix is also suggested based on the results of the present study.

Railway networks impose nuisances like vibration and noise onto structures and the inhabitants proximate to railway lines. Tremendous increase in number of passengers and freight carried across stations has led to faster trains with high axle loads and longer trains with added number of coaches. Passage of trains over railway tracks causes elastic rebound of the railway embankment and ground during the loading and unloading cycle of the railway track, which induces ground vibrations in the railway track foundation. These ground-borne railway vibrations propagate through the railway embankment and supporting ground onto the proximate buildings, which amplify through the height of the structure, causing severe disturbances in the buildings. This study characterises the propagation of ground vibrations generated by a high-speed train wheel travelling at the speeds from 160 to 200 km/h. The temporal variation of ground vibrations was monitored at various depths in the supporting ground and at various horizontal distances away from the track along the ground surface. Results from this study indicate that strong ground vibrations remain in the ground, even after passage of the train wheels to farther distances. Slower train speeds induce stronger ground vibrations in the areas proximate to railway lines, and faster trains generate larger ground vibrations at farther distances from the railway track. It was also ascertained that the railway embankment and supporting ground undergo severe ground motions during the passage of multiple wheels of a high-speed train.